Resource management performance in Bahrain: a systematic analysis of municipal waste management, secondary material flows and organizational aspects

Exposure, knowledge, and perceptions of hazards associated with solid waste management at the household level in jigjiga town, northeast Ethiopia

The goal of this study is to look into household exposure, knowledge, and perceptions of the risks connected with solid waste management in Jigjiga, Ethiopia. Jigjiga is currently grappling with overflowing landfills and limited waste collection, resulting in open dumping and serious health concerns such as disease transmission. The goal of this research is to better understand how Jigjiga residents interact with the waste management system, as well as their perceptions of the health and environmental issues that arise. The study employed a cross-sectional design using a multistage sampling technique. Two kebeles were used to select 200 families living near and far from the dumpsite. Questionnaires were utilized to collect data on demographics, exposure, knowledge, and risk perception. The analysis was carried out utilizing descriptive statistics and binary logistic regression. A survey of 357 households in Jigjiga, Ethiopia, found concerning trends in solid waste management. 78 % of the population visits the dumpsite on a weekly basis, with the majority residing within a 3-km radius. Almost half (44.5 %) reported monthly visits. Despite this, more than 90 % of locals are aware of the health dangers connected with poor waste management. 72 % of individuals believe that inadequate waste disposal causes to illness, with diarrhea being the most prevalent health concern. This study sheds light on the exposure, understanding, and perceptions of risks associated with solid waste management at the household level in Jigjiga, Ethiopia. The findings highlight the significance of improving solid waste management processes to mitigate the negative consequences on human health, the environment, and the economy.

Formal and informal solid waste management in Kutaisi, Georgia: A status quo report based on material flow analysis

The goal of this study is a qualitative and quantitative evaluation of processes and flows within the solid waste management (WM) system in Kutaisi, Georgia, and the wider Imereti region. The applied methodology based upon data collected through customized questionnaires enabled both the formal and informal sectors (IS) to be characterized. Moreover, waste composition studies in the region's rural and semi-urban areas revealed that the share of recyclables is higher in urban areas and commercial centres. A material flow analysis was used to transparently consolidate the collected data, showing that dumping and landfilling still play a major role within the Georgian WM system. The total amount of waste landfilled on 'Nikea' landfill in 2019 equals 58,000 tonnes year^-1, from where around 55,500 tonnes year^-1 is formally collected municipal solid waste, and 2,503 tonnes year^-1 is commercial and industrial waste. According to the findings, the size of the IS in Kutaisi is 0.07-0.15% of the city's population, whose supposed cumulative income is estimated GEL 0.57-1.13 million (EUR 180-360 thousand) in 2019. Informally collected recyclables are estimated 870-1,750 tonnes year^-1, comprising 6-11% of recyclables landfilled in Kutaisi in 2019. The study provides a basis for decision-makers. Replicating the applied methodologies and approaches to create this sound database could support the WM system across whole Georgia. The study further reveals the importance of the need to stop neglecting the IS and recognizes the importance of its role in the WM system of Kutaisi and the wider Imereti region, respectively.

Material flow analysis of plastic waste in the gulf co-operation countries (GCC) and the Arabian gulf: Focusing on Qatar

Global plastic waste production has increased dramatically in recent years, both globally and regionally, having a multitude of adverse effects on the environment and human health. However, little attention has been directed to this problem in the Arabian Gulf region. This study aims to delineate and map the status of the plastic waste problem in the Gulf Co-operation Countries (GCC), with a focus on Qatar. The study focuses on the plastic waste in the marine environment, depicting the different types, sizes and shapes of plastic particles found in the Arabian Gulf. To depict the flow of plastic waste, a generic material flow diagram was built using a material flow analysis software named STAN, in which transfer coefficients were assigned based on existing scientific literature and estimations built on data from local industries and recycling facilities. The recovery and recycling efforts that have been made by the different GCC countries, in efforts to reduce plastic waste and minimize the risk of plastic on the environment are analyzed, too. Our analyses indicate that approximately 11.9 Mt ± 595.395 Kt of plastic waste is produced annually in the GCC region, of which only 23 ± 15% is recycled, indicating that improvements are yet to be made in the recovery, recycling and treatment of plastics in the region. However, in Qatar, a higher percentage of plastics (40 ± 10%) is recovered-recycled with efforts to treat plastics and reuse it to generate energy.

The nine development bands: A conceptual framework and global theory for waste and development

Solid waste management (SWM) is an essential utility service. More than two to three billion people worldwide still lack basic services, whereas some countries are already moving beyond SWM towards waste and resource management (WaRM) and a circular economy. This paper sets out a novel conceptual framework and global theory of waste and development, providing a road map, allowing a country or city to locate their current position and plot their way ahead. We identify nine development bands (9DBs) with significant commonalities in terms of critical challenges and developmental pressure points. DB1-DB4 reflect stepwise improvement towards the new baseline of meeting the SDG 11.6.1 indicators of universal collection and management in controlled facilities (DB5). Countries can then choose to move towards environmentally sound management and the 'reduce, reuse, recycle' (3Rs) (DB6-9), with an ultimate aspiration of 'zero waste'. We test the 9DBs conceptual framework against historical journeys of higher income countries. The main application will be in low- and middle-income countries striving towards SDG 11.6.1, where it fills a key gap in the practitioners' toolkit by enabling initial framing/scoping of the problem and smarter interventions to be designed and sense checked. Key insights include targeted governance/institutional reforms, appropriate and affordable systems/technology and adapting solutions to a diversity of local needs and realities.

Determinants of Household Solid Waste Generation and Composition in Homs City, Syria

The absence of accurate information on the state of waste is a challenge to the solid waste management system in Syria. The local authorities commonly estimate the quantity of waste produced and its characterisation, which is the starting point for solid waste management planning. So, this paper aims to evaluate the generation and composition of household solid waste in Homs city, Syria. Also, the study presents factors influencing the waste generation rate and the waste composition. The study was carried out in 300 families from four zones in Homs city, and three sampling stages were conducted during the study duration, which started in July 2017 and ended in February 2019. The outcomes show that an average of 0.68 kg/per/day solid waste generated was calculated for the entire study area in Homs city. Also, the data analysis presents that organic waste constitutes the largest component in the waste mixture (69.1%) followed by plastic (10.6%), inert materials (8.7%), paper (4.6%), textile (2.5%), metal (1.2%), glass (1.1%), wood (0.6%), and hazardous materials (1.6%). The multiple linear regression results showed that the adjusted R 2 value was found to be 0.557, 0.839, and 0.709 for the waste generation per capita, the daily household organic waste generation, and the daily household packaging waste generation, respectively. Also, according to Pearson's coefficient values, a positive correlation was found between household waste generation and monthly income (r = 0.626), household size (r = 0.37), and age of the household head (r = 0.517), whereas a negative correlation was found between household waste generation and the education level of the household head (r = -0.649).

Quantification of landfill gas generation and renewable energy potential in arid countries: Case study of Bahrain

Sustainable solid waste management can provide pathways for renewable energy generation. The Kingdom of Bahrain has witnessed burgeoning municipal solid waste (MSW) generation rate due to socio-economic development. The authorities of this Small Island Developing State, which is located in arid environment, plan to produce 5% of the total electricity demand from renewable energy sources by 2025 and then double it to 10% by 2035. The US Environmental Protection Agency's Landfill Gas Emission Model software was used to estimate the generation of biogas from MSW at the Askar Landfill site. Results envisaged that maximum landfill gas (LFG) emission rates will be in 2020 following landfill closure by the end of 2019, as an intentional scenario, with a maximum electricity generation potential of 57.4 GWh that could provide power to 488 households. Revenues from carbon credits and electricity sales were US$97.8 million and US$64.8 million, respectively, for the period 2020-2035. The internal combustion engine exhibited the most viable option based on economic analysis of the cost of alternative LFG energy recovery technologies. Our work highlights the potential to use LFG-to-energy technologies to reduce the carbon footprint in arid climates for developing countries with substantial electricity subsidization.

Estimation of plastic waste inputs from land into the Persian Gulf and the Gulf of Oman: An environmental disaster, scientific and social concerns

It has been reported that, the huge amount of plastic waste is present in marine environments. This study evaluated solid waste generation, management, disposal approaches, and the amount of plastic waste entered into the Persian Gulf and the Gulf of Oman in 2016. The findings showed that waste in the Persian Gulf and the Gulf of Oman regions has been mismanaged by 65% and 81%, respectively. According to our estimates, about 1634.9 k-tons (Kt) and 204.6 Kt of plastic waste have been, respectively, generated by the Persian Gulf and the Gulf of Oman littoral states in 2016. Most likely, the mass of plastic waste entering the Persian Gulf and the Gulf of Oman in 2016 was ranged from 155 to 413.4 Kt and 29.2-77.9 Kt, respectively. Without implementation of effective waste management strategies, it is estimated that by 2030, the mass of plastic waste entering the Persian Gulf will increase to 199.4-531.6 Kt, while in the Gulf of Oman it would be about 40.4-107.7 Kt. The entry of plastic waste into the Persian Gulf and the Gulf of Oman has been expected to increase by 29% and 38% in 2030, respectively. As a result, the related cumulative environmental and health effects can be more intensive. It can be emphasized that all countries located in the coastal areas of the Persian Gulf and the Gulf of Oman need to modify their solid waste management, plastic waste in particular, policies to conserve sensitive marine ecosystems.

Mitigation of CO2e Emissions from the Municipal Solid Waste Sector in the Kingdom of Bahrain

Mitigating climate change to limit the global temperature increase (relative to pre-industrial temperatures) to 2 °C is receiving considerable attention around the world. Here, historical and future carbon dioxide equivalent (CO2e) emissions from municipal solid waste (MSW) in Bahrain were calculated using the revised Intergovernmental Panel on Climate Change (IPCC) 1996 and IPCC 2006 methods. The extent to which waste-to-energy (WtE) technologies can contribute to climate change mitigation was assessed by performing a multicriteria analysis. The results indicated that CO2e emissions from MSW in Bahrain have been increasing since the Askar landfill was constructed in 1986. Emission recalculations indicated that CO2e emissions from MSW contribute 6.2% of total emissions in Bahrain rather than the 11.6% reported in the second national communication. Methane emissions from MSW in 2030 are predicted to be 22–63 Gg. The WtE technologies anaerobic digestion and landfill gas recovery gave the best and gasification the worst multicriteria analysis model results. A database of WtE plants around the world should be compiled to allow decisions around the world to be based on best practices. The potential for maximizing energy recovery and decreasing costs needs to be investigated to allow WtE plants to compete better with renewable and nonrenewable energy sources.

Benchmarking performance of solid waste management and recycling systems in East Africa: Comparing Kigali Rwanda with other major cities

This paper aims to benchmark performance of combined solid waste management (SWM) and recycling systems in major cities of East Africa. The Wasteaware indicators are used to present a detailed systems analysis for Kigali in Rwanda, including a mass flow diagram; comparative data are taken from the Wasteaware database for Dar es Salaam, Tanzania, Kampala, Uganda, Nairobi, Kenya, and also for neighboring Maputo, Mozambique. The stand-out result is the relatively high collection coverage achieved, in Maputo with extensive international technical assistance, and in Kigali using its own local resources. In both cases, governance factors are key. Kigali uses a public-private partnership, with exclusive franchises in 35 sectors being tendered every three years; households pay an affordable fee depending on their ability to pay (the service is free to the poorest category); and 95% fee collection rates are achieved, partly through co-collection with charges for local security patrols, which is a service people value highly given the recent history of the country. Another key priority to improve SWM across East Africa is to eliminate open dumping - only Kampala currently has an engineered disposal site. Recycling rates also need to be increased - only Nairobi currently has a good baseline to build on (30%). Common weaknesses include a lack of segregation at source, of institutional capacity, and of available and reliable waste data.

Municipal solid waste management: Constraints and opportunities to improve capacity of local government authorities of Phnom Penh Capital

Solid waste management is a challenge for Phnom Penh city owing to the increasing volume of waste produced and insufficient collection capacity. Sustainable management is required in response to continuing population growth and urbanisation. This article aims to examine the status and constraints of solid waste management in Phnom Penh and discuss the performance of local government authorities to propose possible mechanisms and strategies to improve the system. Data were collected through literature reviews, key informant interviews and focus group discussions with the local government authorities. Six performance measures were used as assessment variables, including technical, environmental, institutional and organisational, financial and economic, social and cultural, and policy and legal factors. Limited institutional capacity and performance are the consequence of insufficient decentralisation power and allocation of budget and workforce for promoting technological and environmentally sustainable practices. Lack of cooperation and coordination among relevant agencies led to their unwillingness to participate in management performance. A decentralisation and provision of management services in the public-private partnership would enable operational procedures that enhance accountability, transparency, efficiency, and productivity at the local level.

The municipal solid waste management of La Paz (Bolivia): Challenges and opportunities for a sustainable development

Municipal solid waste management (MSWM) is considered an important public health, economic and environmental concern, especially in developing countries. This paper introduces the situation of MSWM in La Paz (Bolivia) in 2016, and is based on the Wasteaware indicators and waste flow analysis, useful tools for classifying and comparing waste treatment and management plans among other countries. Taking into account the lack of technology in waste treatment and the presence of a developed informal sector, the paper analyses the main strengths and weak points for implementing a sustainable MSWM. The research conducted revealed that the MSWM of La Paz is not efficient with regard to collection, recycling (8%), financial sustainability, and equity of the service. At the same time, local Government and stakeholders are interested in implementing new MSWM methods for improving the current sanitary state of the city and many efforts were made over the last ten years. In general terms, La Paz could be considered as a good study area for developing plans for waste valorization, becoming an example for a low-middle income developing big city of Latin America. The study provided a few considerations about the affordability of the methodology applied and critically analyzed the case study proposed.

Operator models for delivering municipal solid waste management services in developing countries. Part A: The evidence base

This article presents the evidence base for 'operator models' - that is, how to deliver a sustainable service through the interaction of the 'client', 'revenue collector' and 'operator' functions - for municipal solid waste management in emerging and developing countries. The companion article addresses a selection of locally appropriate operator models. The evidence shows that no 'standard' operator model is effective in all developing countries and circumstances. Each city uses a mix of different operator models; 134 cases showed on average 2.5 models per city, each applying to different elements of municipal solid waste management - that is, street sweeping, primary collection, secondary collection, transfer, recycling, resource recovery and disposal or a combination. Operator models were analysed in detail for 28 case studies; the article summarises evidence across all elements and in more detail for waste collection. Operators fall into three main groups: The public sector, formal private sector, and micro-service providers including micro-, community-based and informal enterprises. Micro-service providers emerge as a common group; they are effective in expanding primary collection service coverage into poor- or peri-urban neighbourhoods and in delivering recycling. Both public and private sector operators can deliver effective services in the appropriate situation; what matters more is a strong client organisation responsible for municipal solid waste management within the municipality, with stable political and financial backing and capacity to manage service delivery. Revenue collection is also integral to operator models: Generally the municipality pays the operator from direct charges and/or indirect taxes, rather than the operator collecting fees directly from the service user.

Material Flow Analysis as a Tool to improve Waste Management Systems: The Case of Austria

This paper demonstrates the power of material flow analysis (MFA) for designing waste management (WM) systems and for supporting decisions with regards to given environmental and resource goals. Based on a comprehensive case study of a nationwide WM-system, advantages and drawbacks of a mass balance approach are discussed. Using the software STAN, a material flow system comprising all relevant inputs, stocks and outputs of wastes, products, residues, and emissions is established and quantified. Material balances on the level of goods and selected substances (C, Cd, Cr, Cu, Fe, Hg, N, Ni, P, Pb, Zn) are developed to characterize this WM-system. The MFA results serve well as a base for further assessments. Based on given goals, stakeholders engaged in this study selected the following seven criteria for evaluating their WM-system: (i) waste input into the system, (ii) export of waste (iii) gaseous emissions from waste treatment plants, (iv) long-term gaseous and liquid emissions from landfills, (v) waste being recycled, (vi) waste for energy recovery, (vii) total waste landfilled. By scenario analysis, strengths and weaknesses of different measures were identified. The results reveal the benefits of a mass balance approach due to redundancy, data consistency, and transparency for optimization, design, and decision making in WM.

Sustainability assessment and prioritisation of e-waste management options in Brazil

Brazil has an increasing rate of e-waste generation, but there are currently few adequate management systems in operation, with the largest share of Waste Electrical and Electronic Equipment (WEEE) going to landfill sites or entering informal chains. The National Solid Waste Policy (2010) enforces the implementation of reverse logistics systems under the shared responsibility of consumers, companies and governments. The objective of this paper is to assess sustainability and prioritise system alternatives for potential implementation in the metropolitan region of Rio de Janeiro. Sustainability criteria and decision alternatives were defined by elicitation of stakeholders. The adopted multicriteria approach combines Life Cycle Assessment with qualitative evaluations by a small sample of regional experts with knowledge of the problem. The recommended system consists of a hybrid WEEE collection scheme with delivery points at shops, metro stations and neighbourhood centres; a pre-treatment phase with the involvement of private companies, cooperatives and social enterprises; and full recycling of all components in the country.

Insights in Waste Management Bioprocesses Using Genomic Tools

Microbial capacities drive waste stabilization and resource recovery in environmental friendly processes. Depending on the composition of waste, a stress-mediated selection process ensures a scenario that generates a specific enrichment of microbial community. These communities dynamically change over a period of time while keeping the performance through the required utilization capacities. Depending on the environmental conditions, these communities select the appropriate partners so as to maintain the desired functional capacities. However, the complexities of these organizations are difficult to study. Individual member ratios and sharing of genetic intelligence collectively decide the enrichment and survival of these communities. The next-generation sequencing options with the depth of structure and function analysis have emerged as a tool that could provide the finer details of the underlying bioprocesses associated and shared in environmental niches. These tools can help in identification of the key biochemical events and monitoring of expression of associated phenotypes that will support the operation and maintenance of waste management systems. In this chapter, we link genomic tools with process optimization and/or management, which could be applied for decision making and/or upscaling. This review describes both, the aerobic and anaerobic, options of waste utilization process with the microbial community functioning as flocs, granules, or biofilms. There are a number of challenges involved in harnessing the microbial community intelligence with associated functional plasticity for efficient extension of microbial capacities for resource recycling and waste management. Mismanaged wastes could lead to undesired genotypes such as antibiotic/multidrug-resistant microbes.

'Wasteaware' benchmark indicators for integrated sustainable waste management in cities

This paper addresses a major problem in international solid waste management, which is twofold: a lack of data, and a lack of consistent data to allow comparison between cities. The paper presents an indicator set for integrated sustainable waste management (ISWM) in cities both North and South, to allow benchmarking of a city's performance, comparing cities and monitoring developments over time. It builds on pioneering work for UN-Habitat's solid waste management in the World's cities. The comprehensive analytical framework of a city's solid waste management system is divided into two overlapping 'triangles' - one comprising the three physical components, i.e. collection, recycling, and disposal, and the other comprising three governance aspects, i.e. inclusivity; financial sustainability; and sound institutions and proactive policies. The indicator set includes essential quantitative indicators as well as qualitative composite indicators. This updated and revised 'Wasteaware' set of ISWM benchmark indicators is the cumulative result of testing various prototypes in more than 50 cities around the world. This experience confirms the utility of indicators in allowing comprehensive performance measurement and comparison of both 'hard' physical components and 'soft' governance aspects; and in prioritising 'next steps' in developing a city's solid waste management system, by identifying both local strengths that can be built on and weak points to be addressed. The Wasteaware ISWM indicators are applicable to a broad range of cities with very different levels of income and solid waste management practices. Their wide application as a standard methodology will help to fill the historical data gap.

Municipal Solid Waste Management using Geographical Information System aided methods: a mini review

Municipal Solid Waste Management (MSWM) is one of the major environmental challenges in developing countries. Many efforts to reduce and recover the wastes have been made, but still land disposal of solid wastes is the most popular one. Finding an environmentally sound landfill site is a challenging task. This paper addresses a mini review on various aspects of MSWM (suitable landfill site selection, route optimization and public acceptance) using the Geographical Information System (GIS) coupled with other tools. The salient features of each of the integrated tools with GIS are discussed in this paper. It is also addressed how GIS can help in optimizing routes for collection of solid wastes from transfer stations to disposal sites to reduce the overall cost of solid waste management. A detailed approach on performing a public acceptance study of a proposed landfill site is presented in this study. The study will help municipal authorities to identify the most effective method of MSWM.

An assessment of the current municipal solid waste management system in Lahore, Pakistan

The current status of solid waste management in Lahore, a metropolitan city of Pakistan, is reviewed in this article using an existing approach, the UN-Habitat city profile. This involves a systematic quantitative and qualitative assessment of physical components and governance features of the current waste management system. A material flow diagram (MFD) is developed, which allows visualisation of the current waste management system with all related inputs and outputs. This study shows that in the current system, waste collection and transportation is the main focus, however the collection coverage is only about 68%. There is no controlled or even semi-controlled waste disposal facility in Lahore. There is no official recycling system in the city. It is estimated that currently ~27% of waste by weight is being recycled through the informal sector. Making use of the organic content of the waste, a composting facility is operative in the city, producing 47,230 tonnes year(-1) of organic compost. Lahore does not perform very well in governance features. Inclusivity of users and providers of the waste management system is low in the city, as not all stakeholders are consulted in the decision making processes. Waste management costs US$20 per tonne of waste, where the main focus is only on waste collection, and the current user fees are much lower than the actual costs. This study recommends that recycling should be promoted by increasing public awareness and integrating the informal sector to make the current system sustainable and financially viable.

Assessment methods for solid waste management: A literature review

Assessment methods are common tools to support decisions regarding waste management. The objective of this review article is to provide guidance for the selection of appropriate evaluation methods. For this purpose, frequently used assessment methods are reviewed, categorised, and summarised. In total, 151 studies have been considered in view of their goals, methodologies, systems investigated, and results regarding economic, environmental, and social issues. A goal shared by all studies is the support of stakeholders. Most studies are based on life cycle assessments, multi-criteria-decision-making, cost-benefit analysis, risk assessments, and benchmarking. Approximately 40% of the reviewed articles are life cycle assessment-based; and more than 50% apply scenario analysis to identify the best waste management options. Most studies focus on municipal solid waste and consider specific environmental loadings. Economic aspects are considered by approximately 50% of the studies, and only a small number evaluate social aspects. The choice of system elements and boundaries varies significantly among the studies; thus, assessment results are sometimes contradictory. Based on the results of this review, we recommend the following considerations when assessing waste management systems: (i) a mass balance approach based on a rigid input-output analysis of the entire system, (ii) a goal-oriented evaluation of the results of the mass balance, which takes into account the intended waste management objectives; and (iii) a transparent and reproducible presentation of the methodology, data, and results.

Waste management and recycling in the former Soviet Union: the City of Bishkek, Kyrgyz Republic (Kyrgyzstan)

The UN-Habitat Integrated Sustainable Waste Management (ISWM) benchmarking methodology was applied to profile the physical and governance features of municipal solid waste (MSW) management in the former Soviet Union city of Bishkek, capital of the Kyrgyz Republic. Most of the ISWM indicators were in the expected range for a low-income city when compared with 20 reference cities. Approximately 240,000 t yr(-1) of MSW is generated in Bishkek (equivalent to 200 kg capita(-1) yr(-1)); collection coverage is over 80% and 90% of waste disposed goes to semi-controlled sites operating with minimal environmental standards. The waste composition was a distinctive feature, with relatively high paper content (20-27% wt.) and intermediate organic content (30-40% wt.). The study provides the first quantitative estimates of informal sector recycling, which is currently unrecognised by the city authorities. Approximately 18% wt. of generated MSW is recycled, representing an estimated annual saving to the city authorities of US$0.7-1.1 million in avoided collection/disposal costs. The waste management system is controlled by a centralised municipal waste enterprise (Tazalyk); therefore, institutional coherence is high relative to lower-middle and low-income cities. However, performance on other governance factors, such as inclusivity and financial sustainability, is variable. Future priorities in Bishkek include extending collection to unserved communities; improving landfill standards; increasing recycling rates through informal sector cooperation; improving data availability; and engaging all stakeholders in waste management strategy decisions. Extending the scope and flexibility of the ISWM protocol is recommended to better represent the variation in conditions that occur in waste management systems in practice.

Comparative analysis of solid waste management in 20 cities

This paper uses the 'lens' of integrated and sustainable waste management (ISWM) to analyse the new data set compiled on 20 cities in six continents for the UN-Habitat flagship publication Solid Waste Management in the World's Cities. The comparative analysis looks first at waste generation rates and waste composition data. A process flow diagram is prepared for each city, as a powerful tool for representing the solid waste system as a whole in a comprehensive but concise way. Benchmark indicators are presented and compared for the three key physical components/drivers: public health and collection; environment and disposal; and resource recovery--and for three governance strategies required to deliver a well-functioning ISWM system: inclusivity; financial sustainability; and sound institutions and pro-active policies. Key insights include the variety and diversity of successful models - there is no 'one size fits all'; the necessity of good, reliable data; the importance of focusing on governance as well as technology; and the need to build on the existing strengths of the city. An example of the latter is the critical role of the informal sector in the cities in many developing countries: it not only delivers recycling rates that are comparable with modern Western systems, but also saves the city authorities millions of dollars in avoided waste collection and disposal costs. This provides the opportunity for win-win solutions, so long as the related wider challenges can be addressed.